1. Field of the Invention
The present invention relates to a projection display system, and more particularly to a color wheel having adhesive-escape-prevention means for use in a projection display system.
2. Description of the Related Art
U.S. Pat. No. 5,868,482 discloses a color wheel that is complicated in structure and wherein the adhesive between the carrier 11 and the filter assembly 12 can escape and flow onto a filter film 17 and can thus result in a contaminated and low quality filter.
To resolve the above-mentioned problem of the color wheel, the inventors of the present invention got an idea to form, at a suitable distance from the periphery of the carrier, a circular-loop-shaped adhesive-escape-prevention groove on the inner surface of the carrier so that in the manufacturing process, the excessive adhesive between the carrier and the filter assembly 12 may flow into the circular-loop-shaped adhesive-escape-prevention groove rather than onto a filter film.
An object of the invention is to provide a color wheel wherein a circular-loop-shaped adhesive-escape-prevention groove is formed on the inner surface of the carrier so that the excessive adhesive between the carrier and the filter assembly may flow into the circular-loop-shaped adhesive-escape-prevention groove rather than onto a filter film.
To achieve the above and other objects, the present invention provides a color wheel comprising a carrier having a central axis, a first principal surface, and a periphery, the carrier being rotatable around the central axis; and a filter assembly having a first principal surface and having the central axis as its central axis, wherein the first principal surface of the carrier is adjacent to the first principal surface of the filter assembly, the first principal surface of the carrier includes a carrier bonding zone, the first principal surface of the filter assembly includes a filter bonding zone, the carrier bonding zone and the filter bonding zone are bound together by an adhesive, a loop-shaped groove is formed around the carrier bonding zone or the filter bonding zone and is apart from the periphery so that an excessive portion, if any, of the adhesive can flow into the loop-shaped groove.